Container closure



March 18, 1969 c. E. KAWCHITCH CONTAINER CLOSURE Filed Oct. 25, 1967United States Patent 3,433,380 CONTAINER CLOSURE Claude EdwardKawchitch, Jolimont, Victoria, Australia, assignor to Loy Bros.Proprietary Limited, Burwood, Victoria, Australia, a corporation ofAustralia Filed Oct. 23, 1967, Ser. No. 677,170 US. Cl. 215-40 Int. Cl.B65d 53/02, 23/02, 41/04 2 Claims ABSTRACT OF THE DISCLOSURE A bottleclosure comprising a disc with a depending peripheral skirt which screwsonto the neck of a bottle, wherein the underside of the disc has acircular groove to engage the mouth rim of the bottle and is covered bya resilient sealing film.

BACKGROUND OF THE INVENTION Field pf the invention This inventionrelates to closures for containers and particularly to caps for bottles.

Description of prior art SUMMARY OF THE INVENTION With a view toovercoming the above mentioned disadvantages of conventional closures,the invention provides a closure for a container, comprising a discportion, a skirt depending from the periphery of the disc portion, acircular groove in the underside of the disc portion adjacent the skirt,the groove having downwardly divergent side walls which in transversecross section of the groove are straight and, on the inner face of theskirt, an internal thread or a plurality of projections arrangedgenerally in the manner of an internal thread.

Preferably too, the closure further comprises a plurality of lugs spacedcircumferentially of the disc portion and projecting above the uppersurface of the disc portion. These lugs are preferably constituted bythe upper ends of a plurality of ribs extending down the outer face ofthe skirt,

Preferably, a film of a resilient material overlays the side walls ofthe groove.

In order that the invention may be more fully explained, one embodimentthereof, and the manner of its use, will now be described in detail withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawings:

FIGURE 1 is an exploded perspective view of the neck of a bottle and aclosure therefor constructed in accordance with the invention;

FIGURE 2 is an exploded vertical sectional view of the bottle neck andclosure of FIGURE 1; and

FIGURE 3 is a vertical sectional view of the closure when fitted to thebottle neck.

The drawings show a closure in the form of a screw cap 11 designed tofit onto the neck of a bottle 12. Cap 11 is moulded from a resilientplastics material, for

Patented Mar. 18, 1969 example a polycarbonate, and comprises a discportion 13 and a generally cylindrical skirt 14 depending from theperiphery of the disc portion. Four external ribs 16 are spaced aroundthe periphery of skirt 14 and project above the upper surface of discportion 13 in the form of lugs 17. At the lower ends of ribs 16, theirouter edges taper inwardly and are rounded at 18.

A circular groove 19 is formed in the underside of disc portion 13immediately adjacent skirt 14. This groove is of inverted truncated Vcross-section so that its side walls are downwardly divergent and thelower part of its outer side wall is bevelled outwardly to form atapered lead 20'. An inverted cup-shaped recess 21 is formed centrallyin the underside of disc portion 13 so that the inner side wall ofgroove 19 is defined by a thin flange 22 which can flex inwardly ofrecess 21.

The underside of cap 11 is fitted with a seal 23 which is vacuum formedfrom a film of an elastomer, for example the elastomer marketed underthe trade name Mylar-Cryovac. Seal 23 comprises a central invertedcup-shaped portion 24 which suits the profile of recess 21 and aperipheral flange 26 which is of inverted truncated V cross-section tosuit the profile of groove 19, a circular groove 27 being formed betweenthe peripheral wall of portion 24 and the flange 26. The outer edge offlange 26 is turned outwardly at 28. As shown in FIGURE 3, cupshapedportion 24 and flange 26 of the seal fit snugly into recess 21 andgroove 19 respectively of the cap. Flange 22 of the cap fits into groove27 of the seal and the outturned edge 28 of the seal fits against thetapered lead 20 of groove 19.

The inner peripheral surface of skirt 14 of the cap is provided with aninternal multi-start screw-thread 29 and in use, the cap is fitted to abottle having a special neck 12. Neck 12 is hollow and generallycylindrical and is provided with external ribs 31 forming a multi-startexternal screw-thread which co-operates with the internal screw-thread29 in the cap so that the cap can be screwed onto the neck of thebottle. At the mouth of the bottle, the inner peripheral surface of theneck diverges conically at 32 in the outward direction toward the rim.The rim 33 is radiused so that it has rounded inner and outer edges 33Aand 33B respectively. The diameter of rim 33 is equal to that of groove19' in the underside of cap 11 and the cone angle of the diverging part32 of the inner peripheral surface of the neck suits the slope of theinner wall of groove 19. When the cap is screwed onto the neck of thebottle, the rim of the bottle enters groove 19 in the cap. The innerwall of groove 19, which is covered by the elastomer film of seal 23,seats on the conical part 32 of the inner peripheral wall of the neckand the rounded outer edge 33B of the neck rim 33 engages the filmcovered outer wall of groove 19 with substantially line contact at 30 sothat there is eflicient sealing of both the inner and outer sides of therim. As the cap is tightened, thin flange 22 forming the inner wall ofgroove 19 flexes inwardly of recess 21 and this resilient deformation ofthe flange provides a radially outwardly biasing force which assists tomaintain a sealing efficiency.

The extreme lower edge 35 of the cap skirt 14 has a slightly smallerunderside diameter than the minor diameter of the multi-start internalscrew-thread 29 (i.e., the diameter of the minor cylinder defined by thecrests of the internal screw-thread) and when the cap is screwed ontothe neck of the bottle, this lower edge 35 engages the neck of thebottle quite firmly with substantial line contact (except where it isrelieved by the internal thread as at 36) whereas there is a slightradial clearance and a slight axial play between the internal andexternal screwthreads. Therefore, the cap is not centralized by thescrewthreads but can rock slightly about the lower edge of its skirt sothat the inner wall of groove 19 will seat correctly on the conicalseating surface 32 of the bottle. The lead of the screw-threads 29, 31,i.e., their inclination from a circumferential direction, may vary alongtheir length in order to provide rapid closure and sealing on rotationof the cap.

The material from which cap v11 is moulded is transparent and the upperand undersides of its disc portion 13 are highly polished so that a beamof light will readily pass through them. The sealing films may then befitted to caps of this type by means of a die having a highly reflecteddie surface and a light source located so as to shine a beam of lighttransversely through the disc portion of the cap towards the die. If forsome reason the die operates without firstly receiving a film seal 23,the light beam will be reflected from the die surface back through thedisc portion 13 of the cap and one or more photo-electric cells may beprovided to detect reflected 'beams and cause a signal whichpreventsfurther operation of the die. When a sealing film is interposedbetween the die and the disc portion of the cap it prevents reflectionof the light beam.

The above described cap and seal provides very eflicient sealing but itcan be readily removed from the bottle without the use of any specialtools. Ribs 16 facilitate gripping of the cap for turning movement and,if the cap is particularly tight, any convenient implement may be placedbetween the upwardly projecting parts 17 of the ribs and turned torelease the cap. Film seal 23 can be readily renewed when the cap is tobe re-used. The downwardly divergent side walls of groove 19 ensure thatsealing contact is made in at least two separated locations even thoughthe exact dimensions of the bottle and cap may vary due to manufacturingtolerances. The rim of the bottle neck need not be rounded on both itsinner and outer edges as shown in the drawings. In fact with some typesof bottle forming machinery it [may be easier to form the rim with a diewhich rounds the outer edge only and forms at the inner edge a rebate orstep which extends between the outer edge and the sloping portion 32. Arim of this type will fit the cap equally as well since 40 its roundedouter edge will engage the outer wall of the groove with substantiallyline contact. The illustrated arrangement has been given merely by wayof example and many modifications and adaptations may be made thereto.For example, the skirt of the cap could be provided with a plurality oflugs arranged in a manner of a multi-start thread in place of thecontinuous internal screw-thread and the gripping lugs could be readilymodified. In place of inverted cup-shaped recess 21 the underside ofdisc portion 13 could be provided with an annular recess locatedimmediately within flange 22 to enable the flange to flex inwardly intoan annular recess. Such an annular recess could, for example, be ofsaw-tooth cross-section.

I claim:

1. A closure for a container comprising a disc portion, a skirtdepending from the periphery of the disc portion, a circular groove inthe underside of the disc portion adjacent the skirt, said groove havingdownwardly divergent side walls which in transverse cross-section of thegroove are straight and, on the inner face of the skirt, means definingan internal screw thread, said skirt having a lower edge which is of asmaller diameter than the minor diameter of the said internal thread.

2. In combination with a closure as claimed in claim 1, a bottle havinga hollow cylindrical neck portion provided with means defining anexternal screw thread which thread engages with the internal thread ofsaid closure, the bottle having a mouth and an inner peripheral surfacediverging conically at the mouth of the bottle in a direction outwardlyof the mouth and providing a seat for the inner side wall of the groovein said closure, said lower edge of the skirt firmly engaging the neckof the bottle, there being a clearance between said internal andexternal screw threads so that the closure element can rock slightlyabout said lower edge of the skirt to insure correct seating of theinner side Wall of the groove and the conically diverging innerperipheral surface of the bottle.

References Cited UNITED STATES PATENTS 3,216,600 11/1965 Dreps 215-403,286,868 1 1/ 1966 Mumford 2l544 X FOREIGN PATENTS 1,049,059 8/ 195 3France.

DONALD F. NORTON, Primary EExaminer.

US. Cl. X.-R.

